• comparatively simple mentality of the Apes forms a
foundation for the study of the complex activities of the human mind. In remote times the earliest true Men had probably simple minds, but the struggle for existence, which included defence, hunting, the building of homes and many other conditions led to a great development of the cerebral functions, and migrations brought them under the influence of varied climatic conditions, which influenced the central nervous system in no small degree.
Variations.—If several examples of each of the Apes are examined it will be found that many of the external characters and internal organs exhibit a considerable range of variation. And some parts vary more than others. So any attempt to define the characters of a species by the examination of one representative will be negatived by the examination of the next animal which conies to hand. In his article on the Gorilla (99) Keith says: " If the animals that make up the p^sent race were superimposed muscle on muscle, artery on artery, brain-convolution on brain-convolution, the result would be, not the clear outline of a typical individual, but rather an amoeboid form, with a considerable amplitude of variation in certain wellrdefined directions . . . the lines of variation thrown out as pseudopodia may be regarded as feelers co-ordinating the race with its surroundings.'* Many of the variations depend on age, sex and the locality in which the particular animal is found; and it is certain that systematists have formed purely local races into distinct species. This is well seen in a study of the literature dealing with the Orang-Outan, for seventeen varieties have been men-